Spray gun

ABSTRACT

The invention relates to a spray gun with a handle part ( 3 ) comprising a safety switch ( 6 ). A nozzle tube ( 1 ) is connected on one end of said handle and a feed line ( 2 ) is connected to the other end thereof. Said spray gun, which can be actuated in a contactless manner by means of an actuating element ( 5 ) and a switch surface ( 4 ), is characterised in that the switch surface ( 4 ) contains an emitting and receiving unit, whereby the active area thereof is disposed in the antenna field ( 8 ) of the switch surface ( 4 ) and is connected to an evaluating device ( 7 ) which is in permanent active communication with the actuating element ( 5 ), which contains an electronic circuit, and which authorises control of the feed supply of the media.

BACKGROUND AND SUMMARY OF THE DISCLOSURE

The present disclosure relates to a spray gun and, more specifically, aspray gun with a safety switch and an on-off switch.

Such spray guns are customarily operated by a liquid medium under highpressure.

Work with spray guns is characterized by high physical stress for theoperator as a result of the high holding and recoil forces, the limitedview because of fog formation and the humid environment. In addition, ahigh risk potential is created by the rebounding of material but mainlyby the high energy content of the liquid jet, normally a water jet. Onthe one hand, this requires a construction with a good ergonomic designand the highest safety standard and, on the other hand, that onlycorrespondingly instructed personnel trained for the work withhigh-pressure water jets are permitted to work with spray guns.

The operation of the spray gun by mechanical or electromechanicaloperating elements is known.

In this case, an on-and-off switching takes place by a manual leverwhich is arranged in the handle part and which can be blocked in aninoperative position by a safety switch. For operating the manual lever,a prior releasing of the safety switch from its locking position istherefore required.

However, the function of the manual lever can be achieved only atrelatively high constructive expenditures. These expenditures comprisemany complicated parts which, on the one hand, require a fairlyexpensive production and, on the other hand, are relatively susceptibleto disturbances. Fragments and residues of the material to be processedby the spray gun may enter into the area of the lever linkage and of thesafety device and block the lever linkage and the safety device.

Mechanical lever systems generally require the application of anoperating or holding force by the operator. In this case, the operator'shand must necessarily always remain in contact with the lever. During afairly long switch-on period, this leads to fatigue or even to cramps inthe switching hands. As a result, safety-critical situations may arise;for example, because of the fact that the switch-off cannot take placeor can only take place in a delayed manner.

It is known from practice that, because of the strained workingposition, the operating personnel frequently fixes the lever devices bysimple means, such as wooden wedges, wire or adhesive tape, againstsafety regulations, in order to reduce the holding force.

In the case of the construction known from German Patent Document DE 8611 018 U1, the operation takes place by contactless electronic proximitysensors, for example, according to the inductive principle. The sensorconverts a physical quantity to an electric signal and utilizes itschange for generating a switching function. Here, the influencingelement, which the operator utilizes for the switching, is of a passivenature in that no communication takes place between the operatingelement and the proximity sensor. This results in the disadvantage ofthis state of the art that the system can easily be disturbed or evenunintentionally switched as a result of outside influences, such asmagnetic or electric fields, vibrations or temperatures. Furthermore,safety regulations are easy to bypass by permanently mounting theoperating element on the proximity sensor, for example, by adhesive tapeor wire. A self-monitoring of the electronic circuit and a checking ofthe access authorization is not possible or not provided.

Depending on the type of construction, the guidance of the medium isalso unsatisfactory in the two constructions. This means thatperformance-reducing turbulences and frictional losses occur as a resultof hydraulic valves and T-shaped or angular connection elements whichimpair the efficiency of such spray guns.

The handling of these spray guns is also unsatisfactory. Particularlyfrom an ergonomic point of view, their extended use may be detrimentalto an operator's health, for example, as a result of muscular tensenessor the like.

The spray gun of the present disclosure has significant advantages incomparison to the state of the art. The contactless actuation of thespray gun without moving parts takes place by an active system which isdistinguished by the fact that the actuating element, preferably atransponder, communicates with a reading station of an electronicevaluating device within the spray gun. As a result, it becomes possibleto ensure the highest possible safety standard for the operator as wellas for persons and objects in his environment.

The transponder is a microelectronic circuit with a transmitting andreceiving antenna, a control logic and a fixedly stored safety code aswell as an energy accumulator which provides the energy for the returnof the safety code. The transponder receives energy packets pulsed atregular intervals from the reading unit of the spray gun and returnsinformation. This takes place by way of antennas in the handle tubewhich are arranged in pairs in order to generate a concentric fieldwithout pole points so that a uniform defined switching interval isensured.

The transponder has a unique identification number which, when it isentered into the antenna field, is sent to the reading unit by thetransponder in order to enable the authorization. This reading unitchecks the identification code and makes a decision concerning theenabling. Thus, it is ensured that only authorized persons can start theoperation of a spray gun and outside influences cause no safety-relevantmalfunctioning.

The transponder is arranged as a separate part, for example, in theuser's finger range. Here, it may, for example, be a component of aglove, a finger ring or a finger covering. The switch-off takes place bymoving the transponder out of the antenna field.

The protection against an unintentional actuating is ensured by a safetyswitch without movable parts, preferably a piezo key. When actuated, thelatter enables the switch-on function for a certain time, specificallyonly when previously no transponder has been situated in the antennafield. As a result, a bypassing of the OFF-function by a permanentmounting of the transponder on the handle pipe, for example, by gluing,is prevented. The enabling time window can be adjusted by an externalevaluating and programming unit and typically amounts to 1–3 seconds.

By way of the program of the evaluating device, the function of acircuit breaker is also assigned to the safety switch. In addition tomoving the transponder out of the antenna field, this provides a secondpossibility of changing the system to a safe pressureless condition.

The reading and evaluating unit is conceived to be self-monitoring, sothat, in the case of defects within the electronic unit, the systemitself is automatically always changed to the safe, that is,non-energized condition. This is achieved by a second transponder whichis fixedly installed on the printed circuit board together with areference antenna. Before each enabling, by inactivating the testingtransponder, the electronic unit internally examines whether anoff-command is taking place. Only when this is properly implemented,will the external switching function be enabled. The signal exchangetakes place dynamically by way of radio communications; that is, with analternating switching of the antennas between the transmitting andreceiving mode, so that a defective final stage of the electronic unitimmediately results in a switch-off.

Furthermore, the present spray gun offers the possibility of readingout, by way of a connected evaluating and programming unit, operatingdata which are detected and stored by the electronic evaluating unit ofthe spray gun, such as switch-on periods with the date and the time, thesummed-up operating duration or the like. These data can be used forcontrolling the working times, as a basis of calculation and planning aswell as in the sense of a preventive servicing and maintenance of thepressure-guiding system. This also results in a significant advantagewith respect to the state of the art, where this has so far not beenpossible.

In addition, by way of an external programming, the spray gun offers thepossibility of a remote control without accessory parts. For thispurpose, an external command is assigned to a certain combination ofsignals of the safety key and of the transponder. Thus, for example, byactuating the safety key three times within a permissible, alsoprogrammable time window, a high-pressure aggregate can be switched onfor supplying the spray gun. In this case, the actuation may beindicated by acoustic signals.

The spray gun is conceived to be essentially independent ofconstructional requirements caused by the function. Thus, for example,the media flow can be optimized; that is, it is to be designed such thatturbulences and/or hydraulic resistance are very slight so that thefriction losses on the whole are minimized. The efficiency of the spraygun is optimized to a considerable extent.

The new spray gun also offers unlimited possibilities with respect to anergonomic design freedom.

As a result of the absence of, in particular, movable components, thespray gun can now be produced at a significantly lower price and is notsusceptible to interfering influences, such as becoming dirty. Also,parts which are subject to wear are eliminated, so that the service lifeof the spray gun is increased, in fact, is virtually unlimited, at leastwith respect to the wear caused by the operation.

The nozzle tube and the feed line are connected with one another in thearea of the handle part by an uninterrupted connection tube. They can bebent in one piece from a tube which has a continuously smooth wall onthe interior side.

The site of the switching is not defined in a punctiform manner but as asurface. Therefore, the user can grip the spray gun at any point of theswitch surface and in the process switch it on and off or leave it inthe switched-on condition.

When the nozzle tube is very short, it is possible that the operator'shand may reach the danger range of the water jet. In order to avoidthis, according to the disclosure, an additional switch surface can beprovided on the handle part, and the operator can be equipped with asecond actuating element. Before an enabling, the electronic evaluatingunit of the spray gun will then examine whether both hands are withinthe range of the switch surfaces and thus outside the danger range ofthe water jet.

Naturally, the spray gun is not limited to a use as a spray gun forliquid media but is definitely also suitable for a use as acompressed-air spray gun.

These and other aspects of the present disclosure will become apparentfrom the following detailed description of the disclosure, whenconsidered in conjunction with accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1 and 2 each are perspective views of an embodiment of a spray gunaccording to the disclosure;

FIG. 3 is a block diagram relating to the signal flow within the spraygun.

FIG. 4 is a functional diagram of the spray gun connected to ahigh-pressure aggregate.

DETAILED DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a spray gun which has a handle part 3, to whose oneend a nozzle tube 1 is connected and to whose other hand a feed line 2is connected.

The feed line 2 may be connected with a high-pressure aggregate 33 (FIG.4).

In the illustrated embodiment, a partial area of the handle part 3 isprovided with a contactless switch surface 4, specifically in the endarea facing the nozzle tube 1.

A safety switch 6 is arranged within the handle part 3, which safetyswitch 6 is electrically connected with an evaluating device 7 in thesame manner as the contactless switch surface 4.

For the operation of the spray gun, the safety switch 6 has to beactuated first, specifically by being touched. Subsequently, forexample, within 1 to 2 seconds, the contactless switch surface 4 has tobe gripped by the user on whose hand a contactless actuating element 5is mounted which includes a safety code. The switching operation istriggered when the actuating element 5 enters an antenna field 8 of theswitch surface 4 or leaves it again.

After each switch-off by way of the switch surfaces 4 and the actuatingelement 5, the safety switch 6 has to be newly activated. As a result, asafety level is reached which is significantly higher than that ofconventional mechanical safety switches.

This switch-on operation is detected by the evaluating unit 7 and istransmitted to a control by which the high-pressure aggregate or anintegrated bypass valve is opened, so that a medium can flow by way ofthe feed line 2 into the nozzle tube 1.

The evaluating unit 7 can additionally be used for the data acquisitionand can be connected to a computer in which the operating data areevaluated.

The contactless switch surface 4 with the antenna field 8 preferablyextends over the complete circumference of the respective area, wherebythe gripping surface is freely selectable. That is, the user can gripthe contactless switch surface 4 for triggering at any point.Expediently, the contactless switch surface 4 and the contactlessactuating element 5 are configured such that no touching of bothcomponents is required. On the contrary, the switching function occursalready when the contactless actuating element 5 is placed approximatelyin an area of up to 30 mm from the contactless switch surfaces 4, whichcorresponds to the radial dimension of the antenna field 8. This permitsan encompassing grip during the operation, during which, after all, thegrip has to be loosened, without immediately switching off the supply ofthe high-pressure water.

FIG. 2 is a perspective view of a spray gun with the arrangement of theactuating elements 5 for a two-hand operation. Constructively, twoswitch surfaces 4 with the respective antenna fields 8 as well as twoactuating elements 5 are provided. In this case, the evaluating unit 7is programmed such that a switching-on can only take place when bothactuating elements 5 are in the area of the switch surfaces 4.

FIG. 3 is a block diagram relating to the signal flow within the spraygun and the method of operation of the evaluating unit 7.

The evaluating unit 7 consists of the following components:

-   -   Microcontroller 9 which carries out the controlling of the        operating sequence as well as the antenna change-overs, the        system checks and the dynamic output signal conditioning;    -   demodulator 10 for the high-frequency signal demodulation;    -   modulator 11 for the high-frequency signal modulation;    -   input amplifier 12 for amplifying the antenna signals;    -   output amplifier 13 for the operation as a transmitting antenna;    -   switch 14 for activating the shield winding of a reference        transponder 15;    -   switch 16, 17, 18 for connecting different antennas to a        transceiver 19;    -   reference transponder 15 which is situated in the interior of        the spray gun and by which the reliability of the system is        checked;    -   working transponder 20 which is moved by the operator from the        outside into the antenna field 8;    -   antenna 21 and antenna 22, which are both offset by 90° and are        activated in an alternating manner in order to eliminate the        pole points of the antennas;    -   reference antenna 23 which is situated in the interior of the        spray gun and by which the reliability of the system is checked;    -   shield winding 24 by which the reference transponder 15 can be        shielded electronically so that it can be checked whether the        transceiver 19 is operating correctly;    -   safety switch 6 which, after being actuated, initiates the        enabling time in which the antenna for the working transponder        20 is cleared;    -   piezo buzzer 25 which acoustically indicates the enabling time        and generates different sounds for facilitating the operation.    -   After the operating voltage is switched on, the high-pressure        signal 34 is first switched to the “OFF” position, and        subsequently a self-control of the system is carried out.        Working and programming memories are checked, and by the        following sequence, the transceiver 19 is checked for its        correct functioning: 1. The microcontroller 9 closes the switch        16 and opens all other switches. It thereby connects the        internal reference antenna 23 to the transceiver 19. Now, the        reference transponder 15, which is mounted in the direct        proximity of the reference antenna 23, is activated and read.

The result has to be identical with the reference code stored in themicrocontroller. When the comparison is positive, Step 2 is nowinitiated. If not, the microcontroller 9 terminates the check and emitsan error code which resets the entire system.

2. The microcontroller 9 now closes switch 14 and switch 16. As aresult, the reference antenna 23 is again connected to the transceiver19. In addition, the shield winding 24 is short-circuited whichenvelopes the reference transponders 15 in a Faraday cage. As a result,the electric field of the reference antenna 23 is kept away from thereference transponder 15, so that the reference antenna 23 can receiveno signal. As a result, the transponder 20 is taken out of the antennafield 8 and not stimulated. Now, no signal must be received. Then it isalso ensured that the entire chain consisting of the input amplifier 12,the output amplifier 13, the modulator 11 and the demodulator 10, thusthe entire transceiver 19, is operating correctly. The transceiver checkwas concluded successfully.

However, if now the signal of the reference transponder 15 were to bereceived, the microcontroller 9 would terminate the check and emit anerror code which then resets the entire system.

This transceiver check is carried out continuously as long as the safetyswitch 6 is not actuated. When the safety switch 6 is pressed, thesystem first switches to the antenna 21, then to the antenna 22 andchecks whether a transponder 20 is situated in the antenna field 8. Onlywhen no transponder 20 is situated in the antenna field 8, will theenabling time be started and be acoustically indicated by an intervalsound from buzzer 25. Now, the microcontroller 9 will always alternatelyscan the two antennas 21 and 22 for the duration of the enabling time.

If a transponder 20 is detected in the antenna field 8 within theenabling time, the high pressure is switched on by a dynamic codedsignal 34. The switch-off takes place either by actuating the safetyswitch 6 or by removing the working transponder 20 from the antennafield 8.

FIG. 4 shows the functional diagram of the spray gun 26 in connectionwith the high-pressure aggregate 33. The high-pressure aggregate 33consists of the pump unit with the driving motor 27, a bypass valve 29fastened on the output side of the pump, a receiver 31 and the control32.

The high-pressure aggregate 33 is connected with the spray gun 26 by wayof the high-pressure line 28 which ensures the feeding of thehigh-pressure water, and the control line 30. By way of the control line30, the signals 34 of the spray gun are guided to the receiver 31 forthe evaluation and from there, to the control 32 which transmits thecommands for the switch-on and switch-off of the high-pressure water tothe bypass valve 29 or, for the start and stop of the aggregate, to thepump unit with the driving motor 27.

Although the present disclosure has been described and illustrated indetail, it is to be clearly understood that this is done by way ofillustration and example only and is not to be taken by way oflimitation. The scope of the present disclosure is to be limited only bythe terms of the appended claims.

1. A spray gun comprising: a handle part having one end connected to a nozzle tube and another end connected to a feed line; a safety switch on the handle part; an antenna on the handle part and having an antenna field adjacent a switch surface of the handle part; a transceiver connected to the antenna; and an evaluating device on the handle part and connected to the safety switch and the transceiver and to media feeding control, the evaluating device actively communicating with an actuating device which contains an electronic circuit and is in the antenna field, and the evaluating device makes a decision on media feeding based on communication with the actuating device.
 2. A spray gun comprising: a handle part having one end connected to a nozzle tube and another end connected to a feed line; a safety switch on the handle part; an antenna on the handle part and having an antenna field adjacent a switch surface of the handle part; a transceiver connected to the antenna; and an evaluating device on the handle part and connected to the safety switch and the transceiver and to media feeding control, the evaluating device actively communicating with an actuating device which contains an electronic circuit and is in the antenna field, and the evaluating device makes a decision on media feeding; and wherein the actuating device includes a safety code transmitted to the evaluating device.
 3. A spray gun comprising: a handle part having one end connected to a nozzle tube and another end connected to a feed line; a safety switch on the handle part; an antenna on the handle part and having an antenna field adjacent a switch surface of the handle part; a transceiver connected to the antenna; and an evaluating device on the handle part and connected to the safety switch and the transceiver and to media feeding control, the evaluating device actively communicating with an actuating device which contains an electronic circuit and is in the antenna field, and the evaluating device makes a decision on media feeding; and wherein the actuating device is a transponder.
 4. A spray gun comprising: a handle part having one end connected to a nozzle tube and another end connected to a feed line; a safety switch on the handle part; an antenna on the handle part and having an antenna field adjacent a switch surface of the handle part; a transceiver connected to the antenna; and an evaluating device on the handle part and connected to the safety switch and the transceiver and to media feeding control, the evaluating device actively communicating with an actuating device which contains an electronic circuit and is in the antenna field, and the evaluating device makes a decision on media feeding; and wherein, when actuated, the safety switch enables a switch-on function within a time window.
 5. The spray gun according to claim 4, wherein a switch-off and remote control functions are implemented by the safety switch.
 6. A spray gun comprising: a handle part having one end connected to a nozzle tube and another end connected to a feed line; a safety switch on the handle part; an antenna on the handle part and having an antenna field adjacent a switch surface of the handle part; a transceiver connected to the antenna; and an evaluating device on the handle part and connected to the safety switch and the transceiver and to media feeding control, the evaluating device actively communicating with an actuating device which contains an electronic circuit and is in the antenna field, and the evaluating device makes a decision on media feeding; and wherein operating data is detected and stored by the evaluating device, which operating data can be read and processed by programming and evaluating units.
 7. The spray gun according to claim 5, wherein functions for remote control and for time-related control can be inputted into the evaluating device by programming and evaluating units.
 8. A spray gun comprising: a handle part having one end connected to a nozzle tube and another end connected to a feed line; a safety switch on the handle part; an antenna on the handle part and having an antenna field adjacent a switch surface of the handle part; a transceiver connected to the antenna; and an evaluating device on the handle part and connected to the safety switch and the transceiver and to media feeding control, the evaluating device actively communicating with an actuating device which contains an electronic circuit and is in the antenna field, and the evaluating device makes a decision on media feeding; and wherein the evaluating device has a circuit for self-monitoring.
 9. The spray gun according to claim 1, wherein the nozzle tube and the feed line consist, without interruption, of one piece in the area of the handle part.
 10. A spray gun comprising: a handle part having one end connected to a nozzle tube and another end connected to a feed line; a safety switch on the handle part; an antenna on the handle part and having an antenna field adjacent a switch surface of the handle part; a transceiver connected to the antenna; and an evaluating device on the handle part and connected to the safety switch and the transceiver and to media feeding control, the evaluating device actively communicating with an actuating device which contains an electronic circuit and is in the antenna field, and the evaluating device makes a decision on media feeding; and wherein a concentric pole-point-free antenna field can be generated in the switch surface by at least two antennas, which are controlled in an alternating manner by the evaluating device.
 11. A spray gun comprising: a handle part having one end connected to a nozzle tube and another end connected to a feed line; a safety switch on the handle part; an antenna on the handle part and having an antenna field adjacent a switch surface of the handle part; a transceiver connected to the antenna; and an evaluating device on the handle part and connected to the safety switch and the transceiver and to media feeding control, the evaluating device actively communicating with an actuating device which contains an electronic circuit and is in the antenna field, and the evaluating device makes a decision on media feeding; and wherein two switch surfaces are present which, for the actuation, both must be brought into an operating connection with corresponding actuating devices.
 12. A spray gun comprising: a handle part having one end connected to a nozzle tube and another end connected to a feed line; a safety switch on the handle part; an antenna on the handle part and having an antenna field adjacent a switch surface of the handle part; a transceiver connected to the antenna; and an evaluating device on the handle part and connected to the safety switch and the transceiver and to media feeding control, the evaluating device actively communicating with an actuating device which contains an electronic circuit and is in the antenna field, and the evaluating device makes a decision on media feeding; and wherein a switch-off and remote control functions are implemented by the safety switch.
 13. A spray gun comprising: a handle part having one end connected to a nozzle tube and another end connected to a feed line; a safety switch on the handle part; an antenna on the handle part and having an antenna field adjacent a switch surface of the handle part; a transceiver connected to the antenna; and an evaluating device on the handle part and connected to the safety switch and the transceiver and to media feeding control, the evaluating device actively communicating with an actuating device which contains an electronic circuit and is in the antenna field, and the evaluating device makes a decision on media feeding; and wherein functions for remote control and for time-related control are inputted into the evaluating device by programming and evaluating units.
 14. The spray gun according to claim 8, wherein the self-monitoring circuit includes a reference antenna and a reference actuating device which are selectively operated by the evaluating device.
 15. The spray gun according to claim 8, wherein the self-monitoring circuit is activated only when the safety switch is not actuated.
 16. A spray gun comprising: a handle part having one end connected to a nozzle tube and another end connected to a feed line; a safety switch on the handle part; an antenna on the handle part and having an antenna field adjacent a switch surface of the handle part; a transceiver connected to the antenna; and an evaluating device on the handle part and connected to the safety switch and the transceiver and to media feeding control, the evaluating device actively communicating with an actuating device which contains an electronic circuit and is in the antenna field, and the evaluating device makes a decision on media feeding; and wherein the evaluating unit activates the media feeding only if the actuating device is not in the antenna field at the actuation of the safety switch and is in the antenna field in a subsequent enabling period after actuation of the safety switch. 